On 06/22/2015 01:32 PM, Viresh Kumar wrote:
'timer_mutex' is required to sync work-handlers of policy->cpus. update_sampling_rate() is just canceling the works and queuing them again. This isn't protecting anything at all in update_sampling_rate() and is not gonna be of any use.
Even if a work-handler is already running for a CPU, cancel_delayed_work_sync() will wait for it to finish.
Drop these unnecessary locks.
Signed-off-by: Viresh Kumar viresh.kumar@linaro.org
Reviewed-by: Preeti U Murthy preeti@linux.vnet.ibm.com
drivers/cpufreq/cpufreq_ondemand.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-)
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index 774bbddae2c9..841e1fa96ee7 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -267,28 +267,20 @@ static void update_sampling_rate(struct dbs_data *dbs_data, dbs_info = &per_cpu(od_cpu_dbs_info, cpu); cpufreq_cpu_put(policy);
mutex_lock(&dbs_info->cdbs.ccdbs->timer_mutex);if (!delayed_work_pending(&dbs_info->cdbs.dwork)) {mutex_unlock(&dbs_info->cdbs.ccdbs->timer_mutex);
if (!delayed_work_pending(&dbs_info->cdbs.dwork)) continue;
}next_sampling = jiffies + usecs_to_jiffies(new_rate); appointed_at = dbs_info->cdbs.dwork.timer.expires;
if (time_before(next_sampling, appointed_at)) {
mutex_unlock(&dbs_info->cdbs.ccdbs->timer_mutex); cancel_delayed_work_sync(&dbs_info->cdbs.dwork);mutex_lock(&dbs_info->cdbs.ccdbs->timer_mutex); gov_queue_work(dbs_data, policy, usecs_to_jiffies(new_rate), cpumask_of(cpu));}
mutex_unlock(&dbs_info->cdbs.ccdbs->timer_mutex);}
}